As a 41-year-old mom of four, Lara Love Hardin knew all the secrets of motherhood: The best snacks to quiet a hangry horde before basketball practice. The telltale wiggle showed a toddler needed the restroom ASAP. 

She also knew the best parking lots to scour for unlocked cars, where she could steal credit cards from other well-heeled moms doing private school drop-off in Aptos, in the suburbs of Santa Cruz, Calif.